1. Field of Invention
The present invention relates to an onboard reception device which is endowed with a noise cancellation function.
2. Description of Related Art
In Japanese Patent Application Publication No. JP-A-06-268539, there is disclosed a noise elimination circuit which, along with controlling the amount of attenuation of an antenna circuit in response to a wide band AGC output signal which corresponds to the strengths of interference radio waves and of radio waves from a desired station, supplies the received signal from the above described antenna circuit to a high pass filter, detects the noise from this output signal, and eliminates the noise in this detected signal by the operation of a gate circuit.
However, there is the following problem with the method of eliminating the noise included in the received signal by, as in the above described related art, along with instantaneously cutting off the received signal by operating a gate circuit when noise has been detected, also performing interpolation processing so as to reduce the distortion of the received signal due to this instantaneous cutting off. That is, if noise is mixed in over a long span of time, or continually, then not only the noise survives, but also distortion of the received signal due to continuous instantaneous cutting off and interpolation becomes prominent, so that it is difficult to eliminate the noise in an effective manner.